Phlogiston (GCMP)David M. WhisnantPhlogiston: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will think back to the last half of the 18th century when modern chemistry was beginning to take place. One of the major problems occupying chemists at the time was combustion. The dominant theory of combustion in the mid-18th century involved a substance called "phlogiston." General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Applications of Chemistry

The Behavior of MaterialsVolume 04, issue 02 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Applications of Chemistry

Chemistry and WarfareVolume 04, issue 09 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Applications of Chemistry

Achievements of Young ChemistsVolume 04, issue 34 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Applications of Chemistry

Special Chemistry Club NumberVolume 05, issue 02 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Meg A. Mole Future ChemistAmerican Chemical SocietyMeg A. Mole visits different chemists to learn about their jobs. She is always amazed at the variety of things that they do.

Applications of Chemistry

Connected ChemistryMike StieffConnected Chemistry, a novel learning environment for teaching chemistry, is appropriate for use in both high school and undergraduate chemistry classrooms. Connected Chemistry comprises several molecular simulations designed to enable instructors to teach chemistry using the perspective of emergent phenomena. That is, it allows students to see observed macro-level chemical phenomena, like many other scientific phenomena, as resultant from the interactions of many individual agents on a micro-level. This perspective is especially appropriate to the study of chemistry where the interactions between multitudes of molecules on the atomic level give rise to the macro-level concepts that students study in the classroom. Connected Chemistry comprises molecular simulations embedded in the NetLogo modeling software (1). The collection contains several predesigned simulations of closed chemical systems to teach specific chemistry concepts. Currently, Connected Chemistry contains models for teaching Brønsted Lowry acid base theory, enzyme kinetics, radical polymerization, buffer chemistry, kinetics, chemical equilibrium, and crystallization. Instructors and students can individually tailor the predesigned simulations or generate new simulations as they are needed in the context of a particular lesson, classroom, or department.

Acids / Bases |

Gases |

Kinetics |

Nuclear / Radiochemistry |

pH |

Titration / Volumetric Analysis |

Polymerization |

Equilibrium |

Catalysis

Molecular Models of Polymers Used in Sports EquipmentWilliam F. ColemanIn keeping with the 2008 National Chemistry Week theme of Having a Ball with Chemistry, the Featured Molecules this month are a number of monomers and their associated polymers taken from a paper by Sandy Van Natta and John P. Williams on polymers used in making equipment for a variety of high-impact sports (1). The molecules provide students with an introduction to an important area of applied chemistry and also enable them to examine complex structures using the models they have seen applied to small molecules.It is certainly instructive for students to build small polymer fragments using molecular model kits. Holding a model of n-decane, for example, and twisting it in various ways, provides real insight into the multiplicity of conformations available to supermolecules of polyethylene. Computer-based 3-dimensional structure drawing and visualization programs make it possible to construct large oligomers of known polymers and to begin to explore structural properties of new systems. Two such programs, free for academic use, are DSVisualizer and ArgusLab (2). DSVisualizer includes a useful set of tools for building and viewing structures and a clean geometry option that applies a Dreiding-like force field. ArgusLab adds the ability to perform both molecular mechanics and semi-empirical geometry optimization and to display various molecular surfaces. Using ArgusLab, or a similar program, students can explore the relative energies of various conformations of the substances they have built electronically. Students who are being introduced to molecular modeling and the use of more sophisticated software can easily explore the effects of the modeling and convergence parameters on the stable structures that are found, and can begin to explore the difference between global and local minima on a molecular potential energy surface. Using the conformational search program in HyperChem 7.5 on a tetramer of vinyl chloride (terminated with H; of SRRS stereochemistry; only CCCC torsions varied), approximately half of the 500 structures examined fell within 6 kcal/mol of the lowest energy structure (3). This number would increase significantly if other torsion angles were included.The use of computational software allows us to introduce students in introductory chemistry to the idea of multiple conformations, which is so important in biochemistry and much of organic chemistry. In teaching ideas behind conformational stability care should be taken when attributing conformational stability solely to non-bonded repulsions between peripheral atoms on adjacent carbon atoms. Weinhold and co-workers have recently presented strong evidence that the stability of the staggered conformer of ethane relative to the eclipsed form arises from more favorable interactions of C-H sigma bonding orbitals on adjacent carbons (4). The multiplicity of such interactions could well be responsible for conformational stability in more complex systems. Any discussion of conformational stability should also introduce students to the ultimate conformational problem, the folding of proteins and to the Folding@home project (5).

Polymerization |

Applications of Chemistry

Creative ChemistryVolume 04, issue 15 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Lake StudyDavid M. Whisnant, James A McCormick, Benjamin Fortin, Patrick NutterLake Study for Windows is a two-part simulation designed to involve students with the scientific method. It allows them to collect data, formulate hypotheses, and test the hypotheses with controlled experiments.

Characteristics of MaterialsAmerican Chemical SocietyWhat makes diapers absorbent? Is peanut butter stickier than syrup or jelly? Strong, stretchy, sticky, or sweet—everything around us has special properties which make them unique. See if you can identify and compare the characteristics of materials.